Time switch



TIME SWITCH Filed Sept. 19, 1928 INVENTOR A TRN vide a switch Patented Aug. 2, 1932 UNITED STATES PATENT OFFH FRANK THORNTON, JR, OF MANSFIELD,

& MANUFACTURING COMPANY,

TIME SWITCH Application filed September 19, 1928. Serial No. 306,814.

My invention relates to time switches and particularly to switches for use with toaster stoves and like electrical heating apparatus.

An object of m invention is to provide a time switch wherein the switch is normally biased toward open position and restrained by a clock escapement and wherein the switchbiasing means serves to drive the escapement mechanism.

Another object of my invention is to pro vide a time switch having the above-noted characteristics wherein a slip connection is provided between the escapement mechanism and the switch which makes possible independent manual operation of the switch.

A further object of my invention is to provide a time switch wherein the connection between the escapement mechanism and the switch includes a latch for automatically disconnecting the switch frcm the escapement mechanism to permit opening movement of the switch when the escapement mechanism has moved a predetermined distance.

A further object of my invention is to prohaving the above-noted characteristics wherein the trip mechanism for the latch may be manually set to trip at a predetermined time or when the escapement mechanism has moved a predetermined distance.

A. further object of my invention is to provide a structure wherein a tumbler switch havingan over-center spring is employed and wherein the operating handle therefor is normally biased toward open position to trip the switch to open'position after predetermined movement, and wherein the escapement mechanism is driven through the medium of the operatin handle andwherein the operating handle is connected to the escapement .mechanism in such manner that manual op eration of the switch is ently of the escapement mechanism.

A further object of my invention is to procomprises aminimum vide a time switch that number of parts and inexpensive to manufacture.

These and other objects that will be made apparent throughout the further description of my invention are attained by means of the T permitted independwhich is compact and Fig. 2 is an end elevational view of the time switch shown in Fig. 1,

Fig. 3 is an elevational view showing parts of the mechanism in different positions than those shown in Fig. 1, and

Fig. 4 is a longitudinal sectional view on line IVIV of Fig. 1.

Referring to the drawing, the time switch comprises a sheet-metal supporting frame 4: consisting of two sheet-metal plates 5 and 6 that are retained in spaced relation by spacing bolts 7.

A tumbler-switch unit 8 is mounted upon the frame and comprises a contact arm 9 hav ing a roller contact 11 on the free end thereof which rolls upon an arcuate insulating track 12 between two operating positions, the switch being shown in Fig. 1 in the open position and in Fig. 3 in the closed position wherein the roller contact engages and bridges two contact members 12, one of which is shown, that are mounted on an insulating block 13.

An operating lever 14 of the bell-crank type is pivoted upon the switch frame 15 at 16,'and a short arm 17 ofthe lever is provided with a pin 18 that operates in a longitudinal slot 19 in the switch arm 9, an overrcenter l spring 21 being mounted upon the arm between the, freeend thcreofand thep in 18, for

the purpose, of ;mo;ving the switch arm and;

roller-contactttoeither of its operating p'osi-fl tions with a snap action when the pin-:18 has been movedover a center line passing through the roller contact -11 and the the center of 'pivot16. i

A spring 22, woundabout the pivot 16 and having its ends engaging the frame 15 and the lever 1 1, serves to normally move the operating handle to an open position; shown in "Fig. 1. By moving the operating handle 14 and forth, the roller contact is moved back into and out of engagement with the contact members 12.

The movement of the operating handle to open position is restrained by an escapement mechanism 23 comprising a driving gear 24 which drives an escapement wheel 25 through a chain of gears 26 and 27, all of which gears are mounted for rotation between the sides and 6 of the frame structure.

Movement of the escapement wheel is controlled by the usual clock escapement mechanism 26 which consists of an escapement arm that oscillates the balance whee 28 in the usual manner.

The driving gear 24 is mounted for rotation upon the shaft 29 and is connected to the 3 shaft through the medium of a slip clutch comprising a pair of spring discs 31 that are secured to, and rotated with, the shaft an which yieldingly clamp the driving gear 24 between them.

A latch plate 32 is secured to the shaft 29 and is releasably connected, through the medium of a pawl 34, to a driving lever 33 that is rotatably mounted upon the stub shaft 40 and which carries the pawl 34. The shaft 40 serves as a pivot mounting for supporting spring for moving the operating handle 14 of the tumbler switch to open position serves to drive the escapement mechanism and will continue to drive it. until the driving connection is disconnected from the latch plate 32 by a releasing movement of the pawl 34 from the latch plate 32.

In order to release mined time or after the escapement mechanism has moved a predeterminedv distance, I have provided the time-control lever 41 that is rotatably mounted upon the shaft 40 l and is provided with a trip arm 42 having a cam face 43 that is adapted to be engaged by a pin 44 carried by the free end of the pawl In Fig. 1, the parts are in the positions that they occupy after the switch has been tripped d to open position, and, in Fig. 3, the parts are shown in the positions they occupy when the switch has been moved to closed position. When the switch is in the closed position shown in Fig. 3, it will be noted that the pin 44 on the pawl 34 lies above the cam face 43 and that it will engage the cam face when it has moved a short distance in a counterclockwise direction. After the pin has ena ed the cam face, further clockwise rotaone end of the shaft 29, as illustrated in Fig. g g

4 which will be hereinafter described.

The pawl 34 is pivoted, at 35, upon the lever 33 and the free end thereof is provided with a tooth 36 which engages a shoulder 37 on the latch plate 32. A coil spring 37, wound about the pivot and having one end engaging the driving lever 33 and the other end engaging the pawl 34, serves to normally bias the pawl 34 toward engagement with the edge of the latch plate 32,

The pivoted end of the pawl 34 is provided with a tooth 37 that engages a shoulder 38 on the latch plate 32 for moving the latch 32 in a clockwise direction when the driving lever 33 is turned in that direction during the closing movement of the switch, in a manner to be hereinafter described.

The operating lever 33 is connected to the operating handle 14 by means of a pivote link 39 in such manner that the lever is rotated in a clockwise direction when the operating handle 14 is similarly rotated to move the switch arm 9 to the closed position shown in Fig. 3. Since the operating handle 14 is biased toward open position by the spring 22, the spring serves to bias the operating lever 33 in a counter-clockwise direction and to rotate the cam plate 32 in a counter-clockwise direction through the medium of the pawl 34 which is in latched engagement with the notch 37 on the latch plate 32.

Since the latch plate 32 is connected to the clutch disc 31 that is fixed to the shaft 29, counter-clockwise movement of the latch late 32 causes similar movement of the driving ear 24 which drives the escapement mechanism. It will thus be seen that the tion of the latch plate 32 causes it to move outwardly over the cam face 43, which, it will be observed, is eccentric to the shaft 29, and cause the tooth 36 to be disengaged from the shoulder 37. When this occurs, the spring 22, which moves the operating handle 14, is free to move the operating handle 14 to open position with a snap action, thereby moving the pin 18 of the switch mechanism over-center and permitting the spring 19 to expand and move the switch-arm 9 to the closed position with a snap action. The time-control lever 41 may be so set that the cam face will be engaged by the tripping pin 44 on the pawl 34 after the pawl and latch plate 32 have been rotated a predetermined distance, the range of adjustment being such that the switch will be tripped open a few seconds-after being set,

1 or a number of minutes thereafter, as desired.

The tripping time 18 minimum when the timecontrol lever 41 is in its extreme right-hand position and maximum when it is in its extreme left-hand position.

By reference to Fig. 4, it will be noted that the stub shaft is riveted to the frame 6 and is provided with an integral or fixed collar 45, the operating lever 33 being rotatable thereon between the collar 45 and the frame 6. The time-control lever 41 is rotatably mounted on the shaft 40 and frictionally retained in said position by means of a. disc spring 46 that is clamped between the lever 41 and the up-turned end of the stub shaft 40 which is provided with a pivot socket 47 gr receiving the pointed end 48 of the shaft Since the operating handle 14 constitutes the pawl 34 at apredeter the driving means for the escapement mechanism, and since it is desirable to open the switch with a snap action, it will be seen that a tumber switch is particularly suitable for operation in combination with the escapement mechanism, because a tumbler switch is not actuated until the operating handle has moved a predetermined distance. It will be seen from the foregoing that I have provided a simple and inexpensive time switch that is particularly well adapted for use with electric toasters and other household electrical appliances and is inexpensive to manufacture and compact in construction.

While I have illustrated but one embodiment of my invention, it will be apparent to those skilled in the art that various changes, modifications, substitutions, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of my invention, as set forth in the appended claims.

I claim as my invention:-

1. The combination with a switch movable to two operating positions, an over-center spring for moving the switch to the said positions, an operating member movable to two operating positions for moving the spring over center when moved in either direction a predetermined distance, and means for biasing the operating member toward one of its operating positions, of an escapement device connected to the operating member and driven thereby for restraining movement thereof to the said position until the escapement de-, vice has moved a predetermined distance.

2. A time switch comprising a movable switch, means for biasing the switch toward one operating position, an escapement train having a driving gear, a slip clutch for the driving gear, means including a latch for connecting the clutch to the switch whereby the former is driven by the latter for driving the driving gear, and an adjustable trip member for tripping the latch and thereby disconnecting the switch from the clutch for permitting independent, operation of the switch after the gear and clutch has turned a predetermined distance.

In testimony whereof, I have hereunto subscribed my name this seventh day of September, 1928.

FRANK THORNTON, JR. 

